Yes, you can trade torque for RPM using various kinds of gearing -- chains, belts, cogs, gearboxes, worm drives, ...Each time you do this, there is some amount of losses, though, so it's almost always better to get the speed/torque conversion you need with the fewest possible steps.

You claim your motor draws too much current. Too much current for what? Get a motor controller and a battery that can drive the motor, or get a smaller motor that matches your controller and battery. Even with PWM to attempt to control the power output of the motor, the amp draw during the PWM "on" cycle will be too big if your controller and battery can't keep up.

You can also reduce the voltage. The amp draw is proportional to the voltage (so the power is square of the voltage, or square of the current draw.) Note that half voltage (and thus half current) will give you one-quarter the power for a given motor.

Torque and speed depends on what wiper motor you get. http://www.robotcombat.com/products/ame_motors.html < here you can find a bunch of them.They vary from about 60 to 180 rpm, which is enough speed as long as your wheels are not very small. Torque is more than enough, with 10-50Nm depending on the motor.I personally bought two AME 120RPM 18Nm wiper motors for my 40LB tracked robot and they run perfectly. Wiper motors are also quite affordable. If you have some extra money and would like something with more power, look to http://banebots.com/ and check out the CIM motor and gearboxes. they are quite expensive but you can get 10x the torque or speed of a wiper motor, depending on the gearbox ratio. Just fyi, they do draw 130A at stall, so you will need a pretty beefy motor controller to fun them. Wiper motors is the best price to torque you can get. Hope this helps!